How does species richness accumulate over time?

2019 ◽  
pp. 189-212
Author(s):  
Timothy G. Barraclough
Keyword(s):  
Phylogenetic Trees ◽  
Species Turnover ◽  
Neutral Theory ◽  
Diversity Patterns ◽  
Extinction Rates ◽  
Neutral Theory Of Biodiversity ◽  
Per Se ◽  
Long Timescales ◽  
Over Time ◽  
Structure Diversity

Species are units for understanding the evolution of diversity over large geographical scales and long timescales. This chapter investigates the processes causing proliferation and demise of species diversity within lineages and regions. Phylogenetic approaches have focused on documenting speciation and extinction rates, but mechanistic theory explaining variation in rates is scarce. Diversity patterns are better explained by geographical and ecological opportunity than by correlates of speciation and extinction rates per se. The neutral theory of biodiversity provides a framework that can be adapted to predict diversity patterns in terms of limits due to competition for space and resources, and species turnover (which cannot be detected directly from phylogenetic trees). These theories bring macroevolutionary and microevolutionary theories closer together. In particular, diversity patterns are the outcome of individual selection and dispersal playing out over long timescales. Some of the processes influencing species patterns can also structure diversity at higher taxonomic levels.

scholarly journals The effects of taxonomic standardization on sampling-standardized estimates of historical diversity

2006 ◽  
Vol 274 (1608) ◽  
pp. 439-444 ◽  
Author(s):  
Peter J Wagner ◽  
Martin Aberhan ◽  
Austin Hendy ◽  
Wolfgang Kiessling
Keyword(s):  
Fossil Record ◽  
Raw Data ◽  
Diversity Patterns ◽  
Genus Level ◽  
Extinction Rates ◽  
Diversity Studies ◽  
Diversity Dynamics ◽  
Over Time

Occurrence-based databases such as the Palaeobiology database (PBDB) provide means of accommodating the heterogeneities of the fossil record when evaluating historical diversity patterns. Although palaeontologists have given ample attention to the effects of taxonomic practice on diversity patterns derived from synoptic databases (those using first and last appearances of taxa), workers have not examined the effects of taxonomic error on occurrence-based diversity studies. Here, we contrast diversity patterns and diversity dynamics between raw data and taxonomically vetted data in the PBDB to evaluate the effects of taxonomic errors. We examine three groups: Palaeozoic gastropods, Jurassic bivalves and Cenozoic bivalves. We contrast genus-level diversity patterns based on: (i) all occurrences assigned to a genus (i.e. both species records and records identifying only the genus), (ii) only occurrences for which a species is identified, and (iii) only occurrences for which a species is identified, but after vetting the genus to which the species is assigned. Extensive generic reassignments elevate origination and extinction rates within Palaeozoic gastropods and origination rates within Cenozoic bivalves. However, vetting increases generic richness markedly only for Cenozoic bivalves, and even then the increase is less than 10%. Moreover, the patterns of standing generic richness are highly similar under all three data treatments. Unless our results are unusual, taxonomic standardization can elevate diversity dynamics in some cases, but it will not greatly change inferred richness over time.

Phanerozoic diversity and neutral theory

Paleobiology ◽  
2015 ◽  
Vol 41 (3) ◽  
pp. 369-376 ◽  
Author(s):  
Steven M. Holland ◽  
Judith A. Sclafani
Keyword(s):  
Body Size ◽  
Primary Productivity ◽  
Marine Invertebrates ◽  
Marine Invertebrate ◽  
Neutral Theory ◽  
Spatial Density ◽  
Individual Probability ◽  
Speciation Rates ◽  
Neutral Theory Of Biodiversity ◽  
Over Time

AbstractAlthough Phanerozoic increases in the global richness, local richness, and evenness of marine invertebrates are well documented, a common explanation for these patterns has been difficult to identify. Evidence is presented here from marine invertebrate communities that there is a Phanerozoic increase in the fundamental biodiversity number (θ), which describes diversity and relative abundance distributions in neutral ecological theory. If marine ecosystems behave according to the rules of Hubbell’s Neutral Theory of Biodiversity and Biogeography, the Phanerozoic increase in θ suggests three possible mechanisms for the parallel increases in global richness, local richness, and evenness: (1) an increase in the per-individual probability of speciation, (2) an increase in the area occupied by marine metacommunities, and (3) an increase in the density (per-area abundance) of marine organisms. Because speciation rates have declined over time and because there is no clear evidence for an increase in metacommunity area through the Phanerozoic, the most likely of these is an increase in the spatial density of marine invertebrates over the Phanerozoic, an interpretation supported by previous studies of fossil abundance. This, coupled with a Phanerozoic rise in body size, suggests that an increase in primary productivity through time is the primary cause of Phanerozoic increases in θ, global richness, local richness, local evenness, abundance, and body size.

scholarly journals How macroecology affects macroevolution: the interplay between extinction intensity and trait-dependent extinction in brachiopods

2019 ◽  
Author(s):  
Peter D. Smits
Keyword(s):  
Species Turnover ◽  
Geographic Range ◽  
Open Ocean ◽  
Strength Increase ◽  
Extinction Rates ◽  
Environmental Preference ◽  
Selection Strength ◽  
Intermediate Preferences ◽  
Average Fitness ◽  
Over Time

AbstractSelection is the force behind differences in fitness, with extinction being the most extreme example of selection. Modern experiments and observations have shown that average fitness and selection strength can vary over time and space. This begs the question: as average fitness increases, does selection strength increase or decrease? The fossil record illustrates how extinction rates have varied through time, with periods of both rapid and slow species turnover. Using Paleozoic brachiopods as a study system, I developed a model to understand how the average taxon duration (i.e. fitness) varies over time, to estimate trait-based differences in taxon durations (i.e. selection), and to measure the amount of correlation between taxon fitness and selection. I find evidence for when extinction intensity increases, selection strength on geographic range also increases. I also find strong evidence for a non-linear relationship between environmental preference for epicontinental versus open-ocean environments and expected taxon duration, where taxa with intermediate preferences are expected to have greater durations than environmental specialists. Finally, I find that taxa which appear more frequently in epicontinental environments will have a greater expected duration than those taxa which prefer open-ocean environments. My analysis supports the conclusions that as extinction intensity increases and average fitness decreases, as happens during a mass extinction, the trait-associated differences in fitness would increase. In contrast, during periods of low extinction intensity when fitness is greater than average, my model predicts that selection associated with geographic range and environmental preference would decrease and be less than average.

DIFFERENCES IN EXTINCTION RATES EXPLAIN CONTRASTING REGIONAL DIVERSITY PATTERNS IN MODERN TROPICAL BRYOZOANS

2017 ◽  
Author(s):  
Jeremy B.C. Jackson ◽  
◽  
Emanuela Di Martino ◽  
Paul D. Taylor ◽  
Kenneth G. Johnson
Keyword(s):  
Diversity Patterns ◽  
Regional Diversity ◽  
Extinction Rates

Community characteristics of forest understory birds along an elevational gradient in the Horn of Africa: A multi-year baseline

The Condor ◽  
2021 ◽  
Author(s):  
Kyle D Kittelberger ◽  
Montague H C Neate-Clegg ◽  
Evan R Buechley ◽  
Çağan Hakkı Şekercioğlu
Keyword(s):  
Species Richness ◽  
Species Turnover ◽  
Survival Rates ◽  
Elevational Gradient ◽  
Forest Understory ◽  
Bird Abundance ◽  
Tropical Mountains ◽  
Demographic Rates ◽  
Understory Birds ◽  
Over Time

Abstract Tropical mountains are global hotspots for birdlife. However, there is a dearth of baseline avifaunal data along elevational gradients, particularly in Africa, limiting our ability to observe and assess changes over time in tropical montane avian communities. In this study, we undertook a multi-year assessment of understory birds along a 1,750 m elevational gradient (1,430–3,186 m) in an Afrotropical moist evergreen montane forest within Ethiopia’s Bale Mountains. Analyzing 6 years of systematic bird-banding data from 5 sites, we describe the patterns of species richness, abundance, community composition, and demographic rates over space and time. We found bimodal patterns in observed and estimated species richness across the elevational gradient (peaking at 1,430 and 2,388 m), although no sites reached asymptotic species richness throughout the study. Species turnover was high across the gradient, though forested sites at mid-elevations resembled each other in species composition. We found significant variation across sites in bird abundance in some of the dietary and habitat guilds. However, we did not find any significant trends in species richness or guild abundances over time. For the majority of analyzed species, capture rates did not change over time and there were no changes in species’ mean elevations. Population growth rates, recruitment rates, and apparent survival rates averaged 1.02, 0.52, and 0.51 respectively, and there were no elevational patterns in demographic rates. This study establishes a multi-year baseline for Afrotropical birds along an elevational gradient in an under-studied international biodiversity hotspot. These data will be critical in assessing the long-term responses of tropical montane birdlife to climate change and habitat degradation.

scholarly journals Fossil biogeography: a new model to infer dispersal, extinction and sampling from palaeontological data

2016 ◽  
Vol 371 (1691) ◽  
pp. 20150225 ◽  
Author(s):  
Daniele Silvestro ◽  
Alexander Zizka ◽  
Christine D. Bacon ◽  
Borja Cascales-Miñana ◽  
Nicolas Salamin ◽  
...  
Keyword(s):  
North America ◽  
Fossil Record ◽  
Phylogenetic Trees ◽  
Phylogenetic Analyses ◽  
Historical Biogeography ◽  
Extinction Rates ◽  
Climatic Cooling ◽  
Fossil Data ◽  
Incomplete Sampling ◽  
Des Model

Methods in historical biogeography have revolutionized our ability to infer the evolution of ancestral geographical ranges from phylogenies of extant taxa, the rates of dispersals, and biotic connectivity among areas. However, extant taxa are likely to provide limited and potentially biased information about past biogeographic processes, due to extinction, asymmetrical dispersals and variable connectivity among areas. Fossil data hold considerable information about past distribution of lineages, but suffer from largely incomplete sampling. Here we present a new dispersal–extinction–sampling (DES) model, which estimates biogeographic parameters using fossil occurrences instead of phylogenetic trees. The model estimates dispersal and extinction rates while explicitly accounting for the incompleteness of the fossil record. Rates can vary between areas and through time, thus providing the opportunity to assess complex scenarios of biogeographic evolution. We implement the DES model in a Bayesian framework and demonstrate through simulations that it can accurately infer all the relevant parameters. We demonstrate the use of our model by analysing the Cenozoic fossil record of land plants and inferring dispersal and extinction rates across Eurasia and North America. Our results show that biogeographic range evolution is not a time-homogeneous process, as assumed in most phylogenetic analyses, but varies through time and between areas. In our empirical assessment, this is shown by the striking predominance of plant dispersals from Eurasia into North America during the Eocene climatic cooling, followed by a shift in the opposite direction, and finally, a balance in biotic interchange since the middle Miocene. We conclude by discussing the potential of fossil-based analyses to test biogeographic hypotheses and improve phylogenetic methods in historical biogeography.

scholarly journals Partitioning the colonization and extinction components of beta diversity: Spatiotemporal species turnover across disturbance gradients

2020 ◽  
Author(s):  
Shinichi Tatsumi ◽  
Joachim Strengbom ◽  
Mihails Čugunovs ◽  
Jari Kouki
Keyword(s):  
Plant Communities ◽  
Beta Diversity ◽  
Species Turnover ◽  
Single Point ◽  
Relative Importance ◽  
Dynamic Nature ◽  
Colonization Dynamics ◽  
Per Se ◽  
The Given ◽  
Temporal Species Turnover

ABSTRACTChanges in species diversity often result from species losses and gains. The dynamic nature of beta diversity (i.e., spatial variation in species composition) that derives from such temporal species turnover, however, has been largely overlooked. Here, we disentangled extinction and colonization components of beta diversity by using the sets of species that went locally extinct and that newly colonized the given sites. We applied this concept of extinction and colonization beta diversity to plant communities that have been repeatedly measured in experimentally disturbed forests. We first found no difference in beta diversity across disturbance gradients when it was analyzed for communities at a single point in time. From this result, we might conclude that disturbance caused no impact on how species assemble across space. However, when we analyzed the extinction and colonization beta diversity, both measures were found to be significantly lower in disturbed sites compared to undisturbed sites. These results indicate that disturbance removed similar subsets of species across space, making communities differentiate, but at the same time induced spatially uniform colonization of new species, causing communities to homogenize. Consequently, the effects of these two processes canceled each other out. The relative importance of extinction and colonization components per se also changed temporally after disturbance. Analyses using extinction and colonization beta diversity allowed us to detect nonrandom dis- and re-assembly dynamics in plant communities. Our results suggest that common practices of analyzing beta diversity at one point in time can mask significant variation driven by disturbance. Acknowledging the extinction–colonization dynamics behind beta diversity is essential for understanding the spatiotemporal organization of biodiversity.

Sign in / Sign up

Export Citation Format

Share Document